WASHINGTON  The universe is about 13 billion years old, slightly younger than previously believed, according to a study that measured the cooling of the embers in ancient dying stars.

Experts said the finding gives "very comparable results" to an earlier study that used a different method to conclude that the universe burst into existence with the theoretical "Big Bang" between 13 and 14 billion years ago.

Harvey B. Richer, an astronomer at the University of British Columbia, said the Hubble Space Telescope gathered images of the faintest dying stars it could find in M4, a star cluster some 7,000 light years away.

Richer said the fading stars, called white dwarfs, are actually burnt out coals of stars that were once up to eight times the size of the sun. After they exhausted their fuel, the stars collapsed into Earth-sized spheres of cooling embers that eventually will turn cold and wink out of sight.

Earlier studies had established the rate of cooling for these stars, said Richer. By looking at the very faintest and oldest white dwarfs possible, astronomers can use this cooling rate to estimate the age of the universe.

Speaking at a news conference Wednesday, Richer said the dimmest of the white dwarfs are about 12.7 billion years old, plus or minus about half a billion years.

Richer said it is estimated that star formation did not begin until about a billion years after the Big Bang. He said this means his best estimate for age of the universe is "about 13 billion years."

Three years ago, astronomers using another method estimated the age at 13 to 14 billion years. That was based on precise measurements of the rate at which galaxies are moving apart, an expansion that started with the Big Bang. They then back-calculated  like running a movie backward  to arrive at the age estimate.

"Our results are in very good agreement" with Richer's estimate, said Wendy L. Freedman, an astronomer at the Carnegie Observatories in Pasadena, Calif., and a leader of the group performing the universe age calculations three years ago.

Bruce Margon, an astronomer at the Space Telescope Science Institute, said both conclusions are based on "a lot of assumptions" but the fact that two independent methods arrived within 10 percent of the same answer is important.

"To find an independent way to measure the age and then get essentially the same answer is a fantastic advance," said Margon. It may not be the final answer for the universe's age, he said, but is "very, very, very close."

To get the new age estimate, the Hubble Space Telescope collected light from M4 for eight days over a 67-day period. Only then did the very faintest of the white dwarfs become visible.

"These are the coolest white dwarf stars that we know about in the universe," said Richer. "These stars get cooler and cooler and less luminous as they age."

He added: "We think we have seen the faintest ones. If we haven't, then we'll have to rethink" the conclusions.

The faintest of the white dwarfs are less than one-billionth the apparent brightness of the dimmest stars visible to the naked eye.

M4 is a globular cluster, thought to be the first group of stars that formed in the Milky Way galaxy, the home galaxy for the sun, early in the history of the universe. There are about 150 globular clusters in the Milky Way; M4 was selected because it is closest to Earth.

The new age estimate for the universe is the latest in a long series of attempts to measure the passage of time since the Big Bang. Edwin Hubble, the famed astronomer who first proved that the universe is uniformly expanding, estimated in 1928 that the universe was two billion years old.

Later studies, using the very expansion that Hubble discovered, arrived at an estimate of about nine billion years for the universe age. This created a paradox for astronomers because some stars were known to be more ancient and it is impossible for stellar bodies to be older than the universe where they formed.

Freedman and others then determined, using proven values for the brightness and distance of certain stars, that the universe throughout its history has not expanded at a constant rate. Instead, the separation of galaxies is actually accelerating, pushed by a poorly understood force known as "dark energy." By adding in calculations for this mysterious force, the Freedman group arrived at the estimate of 13 to 14 billion years.

I was referring to "astronomers using another method estimated the age at 13 to 14 billion years." 14,000,000,000 minus 13,000,000,000 equals 1,000,000,000 years. If the actual age of earth was 13,000,000,000 years and they guessed 14,000,000,000 years, they were within 1,000,000,000 years worst case.

My cynicism for the wide range of years for the age of the earth is borne from the periodically-appearing news reports that yet another "scientist" or "group of scientists" has determined that the earth is really _______ (fill in the blank) years old.

20 years ago, give or take a few years, the consensus was that the Universe was somewhere between 10 and 20 billion years old. There was a fair amount of "slop" in their estimates at that point in time. Today, they have more refined techniques available, and much more data. So they now think it's about 13.5 (+/- 0.5) billion years old, which is well withing the estimates of 20 years ago.

OK, I'll say it in laymen's terms so you can find yourself -IMO, these scientists are blowing hot air and wasting taxpayers money. The universe has been around longer than thirteen billion years, and I don't need 12 years of college education to come to that conclusion.

So what's the furthest distance from me that anything in the universe can be?

If the Inflationary Cosmology is correct, and thus the geometry of Space is Euclidean (or even if Inflation is wrong, but space is still Euclidean or Hyperbolic), there should be no limit on distance between two points in the Universe. If the Universe is closed, the maximum distance is finite.

Note: this is not the same as the maximum distance we can measure another object from us.

They're always working with the data they have. When new data arrives, from new telescopes and better technology, what do you suggest they do? Supress the new information? They don't do that. They welcome the opportunity to revise their understanding, in the light of the best available information. Why do you find this objectionable?

I don't.Maybe it's how you worded it or how I read it, but you made it sound like that it was now pretty much a settled thing because so many of them agreed with each other.

When in fact many things that seemed settled 20 years ago..... today aren't.New information will show up and everything will change.I try and keep up with all this but there are still huge unsettled speculations that this is all built on.So you can read all you want but you'll be much more ignorant when you finish than when you began.Because you will have a better feeling for how little we really know.

On post #35, I stated that it's my opinion the universe goes on in infinity, there are galaxies way beyond what we can see. If this true, then they'll never know the real age of the universe because as of now they're basing their theories only on what our limited technology can show them. The scientists, or at least some of them apparently believe the universe has an ending.

In 1998, Pearlmutter announced a supernova that exploded 10 billion years ago and that was estimated to be 18 billion light years away. There must be a lot of dark energy acceleration at work to push it that far away, since light speed would limit things in the Universe to being 13 billion light years apart otherwise. The greater the acceleration, the larger the estimate should become, as far as I know.

Personally, I believe the discoveries coming, will turn physics and cosmology on it's head and blow lid off just about everything once thought to be credible and established theories. I base this on the advances computers and telescope technology.

The greater the acceleration, the larger the estimate should become, as far as I know.

This was discussed in the press conference today.

The greater the "repulsive" effect (dark energy?), the older the Universe is, relative to the age that would be acertained by the Hubble parameter alone.

The example given in the press conference was that based only on Hubble expansion observations (no repulsion/accelerating expansion effect), the age of the Universe would be about 9 billion years. When they factored in the repulsive effects on expansion, the result was about 14 billion years, which coincidentaly, is almost exactly the figure that these scientists came up with using the completely independent white dwarf cooling model methodology.

I apologize, I was engaging in a little hyperbole.Just trying to make the point that an argument from consensus is flawed.They all come to the same conclusion because they all use the same model.But there are huge assumptions underlying the current popular model, most of which still have little support.

Thus I'll bide my time and keep a jaundiced eye on the whole endevor.For instance the use of a globular cluster to arrive at this data point is fraught with difficulties since the age distribution of stars in globular clusters varies significantly from that of our galaxy.We have no idea how they form.Or even why they are where they are.

Because you stated it as though having multiple independent methods would, incontrovertably, seal your argument for the age of the universe. I was simply pointing out that that is not necessarily the case. Do you agree or not?

Please cite evidence for "a lot longer than thirteen billion years" from a refereed journal. Any such evidence would certainly be of interest.

It's only my opinion that the universe goes on much farther than we know, so predicting its age is not possible. If there are galaxies 100 trillion light years away we can't see, then that means the universe is at least 100 trillion years old.

Huh? Can't be. Just two weeks ago astronomers announced they had discovered the oldest galactic cluster yet, 13.5 billion light years distant. It took at least a billion years for such clusters to form after the Big Bang, putting the age of the Universe at no less than about 15 billion years old. But I do love these contradictions!

Well, what do we see? When we look at distant galaxies we see something called spectral redshifts -- doppler shifts in the spectral emissions of well known elements. Everywhere we look these objects seem to be moving away from us. How odd. The closer ones are moving away slower, and the farther ones are moving away faster.

If you project those motions backward, it is inescapable that we came from a central point -- a "big bang."

Well, how long ago? We know the rate of speed because the doppler shift obeys specific physical laws. We didn't initially know the distances.

One of the earliest methods was to use the brightness of a certain class of variable stars, called Cephids. They could use paralax, triangulation, on close Cephids and get a correlation between their rate of variation, their brightness, and hence their distance. This seemed a good plan because the Cephids were remarkably uniform in that regard. They were a good measuring stick.

So that was one of the early estimates of the size of the universe. But eventually a second class of Cephids were discovered and all the brightness/rate variaition/ distance calculations had to be recomputed.

Those are the two early methods I can recall off the top of my head.

So we haven't seen anything further out than these most distant objects, and they all have that receding redshift indicative of being sourced from the central big bang. So that puts an upper limit on the age of the universe and the Cephid (and now other means) puts a limit on the distance.

There is no evidence that the universe is infinite nor more than 14 billion years old. I won't speculate beyond the limits of evidence.

Good question. My next door neighbor said something long time ago that stuck with me - "how big is big"? In other words, what seems enormous to us may be nothing compared to something else. What he meant was it's possible we're just beings inside some other life form, and if that's the case the universe would not be infinite.

It would make more sense to me if it was an estimate of the current distance. An estimate of the distance seen, instead, would be more directly based on the red-shift. I think they should give both distances, to make it clear.

For instance the use of a globular cluster to arrive at this data point is fraught with difficulties since the age distribution of stars in globular clusters varies significantly from that of our galaxy.

Oh, but the age disparity is precisely what makes this methodology so useful. Globular clusters have the OLDEST stars in the galaxy. They look at the oldest stars in the galaxy, and then looked for the faintest white dwarfs among them (meaning the oldest of the oldest, so to speak).

Thus, the age of the oldest visible white dwarf defines a lower bound for the age of the Universe. To this age (12.7 x 109) they add a billion years, which is the minimum estimate of the length of time it takes for stars to form AFTER the Universe started. Thus the minimum age for the Universe is 13.7 billion years (+/- 0.5 billion) by this method.

Not at all. The idea of universes inside of universes is much easier on the brain than the idea of a single Big Bang universe or even an infinity of Big Bang universes coming out of a higher dimension.

My understanding is that the acceleration rates in most models have different epochs, with plateus and peaks, rather than being a constant or exponential acceleration. There are more than a few distinctly different epoch models, as far as I know.

Interesting paper. I cannot connect to New Scientist from here so I can't see what the actual idea is. One problem I can see (from the Oz site which may be incomplete) is that the dark matter and dark energy stuff seems to be spread out within the universe. The web site talks about contracting regions which isn't the same as the entire universe contraction. Thanks for finding it.

Without adding the quotation marks and without referencing the websites, which are easily found by entering +universe +age +billion into the search field on google.com:

1. the age of the universe is apparently 8 to 12 billion years 2. the age of the Universe would be 8-11 billion years 3. the new 13 billion year estimated age of the Universe 4. the age of the universe as inferred from the Hubble constant would be about 9 billion years 5. EVOLUTIONARY AGE OF THE UNIVERSE 14-15 billion years 6. the Hubble constant and the geometry of the Universe typically yield ages of 10-20 billion years for the age of the Universe 7. while previous calculations meant estimates of the universe's age could vary by as much as 10 billion years 8. the "best, ie, most consistent, age of the universe is estimated to be 14-17 billion years 9. the Universe's age drops to 7--15 billion years 10. the age of the universe of 7.5 billion years 11. Present estimates for the universe's age range from eight to twenty billion years 12. Estimates range from as low as about 10 billion years to as high as 40 billion years 13. So it seems safe to estimate that the age of the Universe is at least 15 billion years old, but probably not more than 20 billion years old 14. is determining the age of the universe. Some measurements of the Hubble constant suggest an age as low as 8 billion years 15. and the universe's age at 9 billion years 16. Recent reports on the age of the universe suggest it's only 8-12 billion years old 17. universe might only be eight or ten billion years old 18. The observations of the density of the universe, favorable to a flat universe lead to an age of the universe of 9 billion years 19. project the age of the universe to be 8 billion years 20. the age of the universe may be as small as 8 billion years 21. the age of the universe is about eight-twelve billion years 22. These new results yield ranges for the age of the Universe from 9-12 billion years, and 11-14 billion years, respectively 23. somewhere between about 7 to 10 billion years ago, when the Universe was between a quarter and half its present age 24. At the present time estimates of the age of the universe range between 7 and 20 billion years 25. such as the age of the Universe which ranges between 17 and 18 billion years

So we haven't seen anything further out than these most distant objects, and they all have that receding redshift indicative of being sourced from the central big bang.

The big bang theory and the expanding universe may be strong possibilities given the research and what we know. But does current technology prevent us from seeing out farther than we do now? Could it even be possible to discover galaxies 100 billion or more light years away? This is why I'm skeptical of any claims to age, because there's so much out there we don't know yet.

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